Who This Checklist Is For

If you're sourcing Momentive silicone sealants, rubber, or foam—and you've found yourself on momentive.com wondering where the technical specs are, or you've ordered casting silicone only to realize it was the wrong durometer—this checklist is for you.

I've been handling orders for specialized rubber and plastic products for about six years now. In that time, I've made (and documented) 14 significant mistakes, totaling roughly $4,200 in wasted budget. This is the checklist I now run through for every single order. It's saved me—and our team—from repeat errors on a 47-piece order where every single item had the wrong density spec (ugh).

The 5-Step Checklist

Step 1: Know What You Actually Need (Product vs. Material)

When I first started using Momentive products, I assumed "silicone rubber" meant one thing. It doesn't. Momentive produces a full spectrum: liquid silicone rubber (LSR), high-consistency rubber (HCR), room-temperature vulcanizing (RTV) silicone, and silicone foam. If you search momentive.com for "foam" without specifying which type, you'll get results for crosslinked PE foam insulation and their silicone foam. They are very different materials.

Action: Before you touch momentive.com, write down exactly what you need. Is it a cured sheet? A liquid for casting? A foam for gasketing? Don't hold me to this, but roughly 40% of my early mistakes were from confusing a raw material search with a finished product search.

Step 2: Use momentive.com for Product Data Sheets, Not Search Results

Momentive.com isn't an Amazon-style catalog. The momentive login portal gives distributors access to documents, but the public side is a knowledge base. A lot of the how-to-cut-insulation-foam-board guidance lives in PDF data sheets, not on the main product pages.

When I was looking for casting silicone—the kind you pour into molds—I assumed I could find a simple "buy now" page. Nope. You need the technical data sheet (TDS) for the specific RTV silicone you want. (I learned this circa 2022, things may have changed.)

Action: Use the search bar on momentive.com with the exact product name (e.g., "Momentive RTV 6208 TDS"). If you search "casting silicone" broadly, you'll get a general result page. For the spec-level details you need, go to the Document Library after logging in via the momentive login portal.

Step 3: Specify Durometer and Density Like Your Budget Depends on It (It Does)

I once ordered 60 units of a silicone foam gasket material. Checked it myself, approved it, processed it. The error came back when the engineer said, "This is crosslinked PE foam, not silicone foam." Wait—no. The real issue was that I had confused the density spec. The part number I ordered was for crosslinked PE foam (XPE) at a 35 kg/m³ density. I needed Momentive silicone foam at a 45 kg/m³ density. $320 order, straight to the trash. Lesson learned: double-check the material identifier, not just the size.

Action: For all foam orders—whether crosslinked PE foam or silicone foam—confirm the material type and density in the data sheet. If a product description says "crosslinked pe foam" and your application is high-temperature sealing, you need silicone foam.

Step 4: Understand the Difference Between Casting Silicone and Mold-Making Silicone

I don't have hard data on industry-wide confusion here, but based on our 5 years of orders, I'd say about 12% of first-time casting orders have the wrong durometer or working time. My repeated attempt was to order a high-durometer (hard) casting silicone for a flexible mold. The numbers said I could use a cheaper grade. My gut said stick with the standard. Went with my gut. Later learned the cheaper grade had a shorter cure time that I hadn't accounted for.

Action: For casting silicone, check three things: (1) Pot life/working time, (2) Shore A durometer, (3) Cure temperature. Momentive's TDS will list all three. If you're doing a hand-pour mold, you typically want a slower cure (30-45 min working time) at room temperature.

The industry standard recommendation for most casting applications is:

Use an RTV-2 silicone (like TSE3450) with a Shore A durometer between 20-30 for flexible molds, and 40-60 for rigid parts. Reference: Momentive TDS library.

Step 5: Verify Your "How to Cut Insulation Foam Board" Assumptions

If you're working with crosslinked PE foam insulation board—which is a different product from Momentive's silicone foam—you need a different cutting strategy.

I learned this in 2023. I had a piece of how-to-cut-insulation-foam-board advice from a coworker who said "just use a utility knife." That works for standard polystyrene foam, but crosslinked PE foam is dense and tough. You need a hot wire cutter or a sharp serrated blade, or you'll end up with ragged edges. On a 200-piece order where every single piece had to fit precisely, the utility knife method cost us a 3-day delay.

Action: If you are cutting Momentive's silicone foam, a sharp blade and a straightedge works well. If you are cutting crosslinked PE foam from another supplier, use a hot wire cutter. Verify which material you have before you start.

Common Mistakes to Avoid

What was best practice in 2020 may not apply in 2025. The fundamentals haven't changed—know your durometer, check your TDS, and verify material type—but the execution has transformed with better document search on momentive.com.

I wish I had tracked this checklist from the start. What I can say anecdotally is that after implementing it, we caught 13 potential errors in the first year alone. A few hundred dollars of mistake potential, caught before it became real waste.